where I can know my gold status expiration date?
Status is good 14 months after the year you achieve it, starting from Jan 1 of the year after achieving it. So, if you achieved Gold last year, it expires Feb 28, 2018 and if you achieved it this year it expires Feb 28, 2019.
Note that this is true of any status, and under the current program rules - once the SPG and Marriott Rewards programs merge, this could change.
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